BUILDING A QUATERNARY STRATIGRAPHIC FRAMEWORK FOR THE OUTER BANKS OF NORTH CAROLINA USING CONCEPTS DERIVED FROM THE GEORGIA COAST: A TRIBUTE TO CLASSIC RESEARCH IN FACIES ANALYSIS BY V.J. HENRY AND HIS COLLEAGUES

From 1964 to the 1980s, V.J. Henry with John H. Hoyt, John A. Hails, Robert W. Frye, James D. Howard, and their students conducted world-class studies of Quaternary barrier islands through the University of Georgia's Marine Institutes at Sapelo and Skidaway Islands. Their study area was the Georgia Coast. Henry, Hoyt and Hails, published papers on barrier island processes, the origin of capes and shoals, Pleistocene stratigraphy and paleoshorelines. Hoyt and Henry (1965) provided a now-classic sketch that showed how a shifting inlet generates a set of inclined stratal surfaces in a sequence comparable in thickness to the inlet depth. Howard and Frye catalogued the attributes of surficial Holocene salt marsh, estuarine, barrier island and shelf facies. Their beach to offshore transition, along with the shifting inlet model, provided bases for interpreting upward-shoaling, shelf parasequences. Howard and students used the Georgia coast as a modern analogue for the Book Cliffs, and helped define the principles of sequence stratigraphy. Recent research in North Carolina has built on this pioneering effort.

In 2002, the U.S. Geological Survey began an integrated framework study of the Outer Banks. The goal is to characterize the Quaternary section (<70 m thick) and sequence stratigraphy between the Outer Banks and the Suffolk Scarp, and tie it in with offshore and backbarrier seismic reflectors, geomorphic processes, paleoshorelines, formal stratigraphic nomenclature, amino zones, and oxygen isotope stages. In 28 rotasonic cores, fluvial, estuarine, shelf and barrier island facies, genetic sequences and bounding surfaces are defined from lithofacies and biofacies analyses (foraminifera, pollen, diatoms). The project's integration team, through multiple lines of evidence and consensus, provides correlations between data sets and the regional stratigraphic framework.

A barrier-parallel cross section near Oregon Inlet (Kill Devil Hills to Rodanthe) shows at least 4 Pleistocene units locally bounded by fluvial facies and overlain by shelf facies. The base of the late Pleistocene to Holocene transgression is marked by a weathered ramp surface that locally is punctuated by paleovalleys, and infilled with fluvial, estuarine, and upward shoaling shelf facies. These are overtopped by shelf and barrier island facies.